Effect of packaging materials and storage periods on the quality of reference Cocoa beans.

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September, 2015
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Reference cocoa beans are cocoa samples that are kept in glass bottles and stored for four months to address problems of discrepancies in quality of beans shipped to their destinations abroad. The beans are later analysed for biochemical, physical and entomological properties for arbitration resolution if the cocoa is found to be inferior at their destinations abroad. During storage, the quality of the beans could be affected by moulds, insects and moisture. This study was, therefore, carried out at the Cocoa Research Institute of Ghana (CRIG) to determine the effect of packaging materials and storage durations on the physical and biochemical quality of reference cocoa beans fermented for six days, dried and stored for four months in a 4 x 5 factorial arrangement in completely randomized design with three replications. Cocoa beans kept for reference were packaged in transparent glass bottles, transparent plastic bottles, transparent high density polyethylene bags and jute sack bags and stored for 30, 60, 90 and 120 days. Physical characteristics of the cocoa beans were studied using the cut test method. AOAC (2005) method was used to determine pH, free fatty acid, fat and moisture contents of the beans. Results from the cut test analyses showed that all the treatments had effect on percentage deep purple, pale purple and brown beans. However, beans packaged in jute sacks and stored for 120 days developed significantly (p = 0.01) the least (13.57%) deep purple beans, than those in glass bottle, plastic bottle and high density polyethylene bag. Jute sacks produced significantly higher (80.51%) amount of brown beans. Beans kept in jute sack bags produced the most desirable physical quality (deep purple, pale purple and brown) of beans. Among the packaging materials tested, jute sack again produced the most desirable biochemical properties in terms of bean pH, free fatty acid, fat and moisture contents. Storing beans for 60 days gave the best physical quality whilst beans stored for 90 days produced the most desirable biochemical quality. Mean temperature and relative humidity did not correlate with biochemical characteristics of cocoa beans kept in the different packaging materials. Overall, beans packaged in jute sack bag and stored during the entire period of 120 days produced the most physical and biochemical qualities. From the study, to maintain quality towards/defend any discrepancies which may arise regarding the quality of beans shipped, reference beans should be stored in jute sacks but in dry cool conditions and protected from insects and dust.
A thesis submitted to the School of Research and Graduate Studies, Kwame Nkrumah University of Science and Technology, in partial fulfillment of the requirements for the award of Master of Philosophy (MPhil. postharvest technology) degree,